www.tjprc.org SCOPUS Indexed Journal editor@tjprc.org PRESSURE TESTING RESULTS (AS A DECISION TOOL FOR DECIDING LOW OXYGEN OR ULTRA-LOW OXYGEN OR HIGH OXYGEN STORAGE) OF SEMI- HERMETICALLY SEALED CONTROLLED ATMOSPHERE STORAGE INSULATED CHAMBERS RAM DESHMUKH 1 , D. RAMESH BABU 2 & K. V. NARASIMHA RAO 3 1 Professor, Department of Electrical Engineering, S R Engineering College, Warangal, Telangana, India 2 Assistant Professor, Department of Mechanical Engineering, S R Engineering college, Warangal, Telangana, India 2 Research Scholar, Department of Mechanical Engineering, Koneru Lakshmaiah Education Foundation, Vaddeswaram, Andhra Pradesh, India 3 Professor, Department of Mechanical Engineering, Koneru Lakshmaiah Education Foundation, Vaddeswaram, Andhra Pradesh, India ABSTRACT Controlled atmosphere storage technology is used widely for storing apples for long term. The very basic need of the construction of the chambers is gas tightness. Low oxygen and high carbon dioxide levels are to be maintained to reduce the respiration and transpiration losses of fruits stored in the Controlled Atmosphere (CA) chambers. Gas tightness becomes important to maintain low oxygen levels. This paper presents the first of its kind of results for gas tightness test results of CA chambers in India. The CA chambers are constructed with factory build Poly Urethane Foam (PUF) panels and assembled at the cold/CA storage site. Ribbstyle make paint along with non-woven cloth is used to join the gaps of the insulation panels. Before storing apples in the chambers, gas tightness test is conducted for checking leakages from the walls. As per the international standard for gas tightness, pressure drop from 10 mm of water column to 3 mm of water column is permitted in 30 minutes of time of inflation. Rate of pressure drop is modeled mathematically, and results are presented. Based on the results of this pneumatic test, future work may be taken up to categorize CAS chambers as Ultra low oxygen storage (less than 0.5% O 2 ), Low oxygen (0.5-2.5% O 2 ) and High oxygen (2.5 – 15% O 2 ) storage chambers and are used for relevant apples. KEYWORDS: Controlled Atmosphere Storage (CAS), Gas Tightness, Elastic Paint, Pneumatic Test, Semi-hermetically Sealed Chamber & Low Oxygen Received: Nov 26, 2019; Accepted: Dec 16, 2019; Published: Jan 31, 2020; Paper Id.: IJMPERDFEB202045 INTRODUCTION Controlled Atmosphere Storage (CAS) is a successful technology in storing fresh fruits for long periods compared to cold storage. A cold storage keeps fruits and vegetables at low temperature which retards the respiration rate and thereby delays ripening. Normal cold store walls are constructed with steel panels with insulation sandwiched between the panels. The insulation materials are polyurethane foam (PUF), glass wool, rock wool or Styrofoam, etc. Controlled atmosphere storage chambers need better insulation with gas tightening. This is due to the requirement of maintaining of low oxygen, high nitrogen and high carbon dioxide within the chamber of fruit storage. A semi-hermetic chamber needs to be constructed for maintaining the low oxygen conditions within the Original Article International Journal of Mechanical and Production Engineering Research and Development (IJMPERD) ISSN(P): 2249–6890; ISSN(E): 2249–8001 Vol. 10, Issue 1, Feb 2020, 531–540 © TJPRC Pvt. Ltd.